Salvation is love, but freedom is the deepest description of the movement of that love. The providence of God is the salvation of the world, of all Creation; it is indeed the enacting of his will in and through history, but the will of God is a *possibilizing* will. Thus all of God's movements in history, in the service of love, are also in the service of freedom.
It is not simply that God desires the love of his creation and that this love requires freedom as a logical condition of possibility, thereby compelling God to reluctantly sacrifice certain souls so that he might settle to have only a portion of his creation be saved.
Rather, salvation, love, and freedom are much the same thing. Salvation without freedom is not merely a logical impossibility; it is absolute contradiction, and God cannot contradict himself. The notion that there is any distinction between God's universal salfivic will, and his liberating, possibilizing will, is an illusion.
The consequence of this is that, if God were to reject or deny any freedom--even the most petty kind, for any reason--he would in the same act be denying that person's salvation. Overpowering someone's will, God displaces the will with his own; and without a will, the person ceases to be a creature in any way open to the love that salvation is.
The last free act that any creature of God's can ever do is to definitively renounce its own freedom. This is damnation itself, but it is precisely God's universal salvific will that makes this free act possible. For God to contradict the mortal sinner's free self-condemnation would be annihilation of the sinner (which is not a mercy) and a contradiction of Himself. Either a person renounces his own freedom, which he can only do incompletely yet also permanently, or God takes it away to prevent him from doing so himself, annihilating the will. The damned, to whom all of this is revealed, become totally enslaved to the vain desire to destroy themselves, to destroy God, and everything else. Their failure to do so increases their hunger for more destruction, and they are not free to desire anything else (hence Hell is everlasting). But to be annihilated is not to be a permanent slave to everlasting self-destruction; it is to be a slave to the only thing which is worse: void.
Added April 29th:
The whole business of God 'annihilating' a person deserves elaboration. The obvious objection is that God would not have to destroy a person, or destroy his free will, in order to prevent him from doing something self-destructive. I grant this. There is, however, a more basic question of whether a person rejects or accepts his own freedom. This transforms the issue.
The forfeiture of freedom is not a mere extrinsic act among many. It ... [interrupted]